Data backup is a valuable tool in safeguarding important data. Data are generally backed-up onto removable data storage items, such as tape cartridges or optical discs, such that the backup data may be stored at a different geographical location to the primary data.
By storing important data onto removable data storage items, security issues become a consideration. For example, a visitor to a site might easily pocket a tape cartridge storing large amounts of commercially sensitive data.
Many backup software packages provide the option of encrypting data prior to backup. A drawback with this approach, however, is that data stored on a particular removable data storage item may be encrypted using various different encryption keys. It is therefore necessary to maintain a database of encryption keys and data pointers for each and every removable data storage item. Maintaining such a database naturally attracts management overheads. Additionally, the database may grow to a significant size, must always be available for access and is itself a potential security risk.